A Specific Aims. The main objectives of this proposal are 1) to develop an efficient, inexpensive method for the generation of contaminant free, reactive ketenes, and 2) to apply this new methodology to a number of diverse catalytic asymmetric transformations that represent important problems in synthetic organic chemistry, including the catalytic, asymmetric synthesis of Beta-lactams; catalytic, asymmetric halogenation reactions; polycomponent or tandem catalytic reactions; and asymmetric catalysis on columns. Most of our proposed methodology depends on the putative intermediacy of enolates derived from the reaction of ketenes and catalytic nucleophiles. All the optically enriched, chiral products of our reactions are meant to be either pharmacologically active, or potentially so, or to represent key intermediates and branch points in the synthesis of medicinally or academically interesting target molecules.